ordinal number


Definition of ordinal number

1 : a number designating the place (such as first, second, or third) occupied by an item in an ordered sequence — see Table of Numbers
2 : a number assigned to an ordered set that designates both the order of its elements and its cardinal number

Examples of ordinal number in a Sentence

Recent Examples on the Web Interestingly enough, Kruskal's tree theorem required non-finite mathmatics to prove, using advanced techniques such as transfinite arithmetic and ordinal numbers. Jay Bennett, Popular Mechanics, "Wrap Your Head Around the Enormity of the Number TREE(3)," 20 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ordinal number.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of ordinal number

1607, in the meaning defined at sense 1

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Time Traveler for ordinal number

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The first known use of ordinal number was in 1607

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Cite this Entry

“Ordinal number.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ordinal%20number. Accessed 24 Nov. 2020.

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More Definitions for ordinal number

ordinal number


English Language Learners Definition of ordinal number

: a number (such as first, fifth, or 22nd) that is used to show the position of someone or something in a series

ordinal number


Kids Definition of ordinal number

: a number that is used to show the place (as first, fifth, 22nd) taken by an element in a series

More from Merriam-Webster on ordinal number

Nglish: Translation of ordinal number for Spanish Speakers

Britannica.com: Encyclopedia article about ordinal number

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